Vapor development resist

The first example of formation of a resist relief image in the absence of a wet developing step was reported by Bowden and Thompson in 1974 (131). They reported that exposure of certain poly(olefin sulfones) to electron beam radiation resulted in spontaneous relief image formation. When the films were cast thin enough and the substrates were heated above 90 C, clean images were produced in the resist film by exposure alone. They termed this phenomenon vapor development . 

Next, the pattern is developed by dissolving the exposed parts of the pattern in the correct solvent. The quality of the pattern (contrast) depends on both the exposure and the development time, both of which must be experimentally determined for different resist systems and substrates. Once the pattern has been exposed and developed, the actual catalytically active metal(s) or oxide(s) is vapor deposited both within the holes in the pol3mier and on top of the polymer (step 5). This metal (or oxide) film should be discontinuous at the pattern boundaries in order to make possible the liftoff the remaining resist. This requires that the resist layer is thicker than the deposited film, and that the developed resist features have an undercut or negative profile... 

Fig. 37. Resist images obtained with a cross-linking monocomponent TSI resist (PHOST polymer), cross-linked by photo-oxidation using light at 193-nm wavelength. After exposure, the film was treated with a vapor of dimethyl silyl dimethyl amine and then plasma developed using O2—RIE (122).

Besides water vapor and gas diffusion, other requirements for good edge sealants are water resistance, uv resistance, heat/cold resistance (—40 to 80°C), adhesion to glass and metal, and good characteristics for appHcation. Polysulfide sealants have maintained an exceUent record in use since the 1950s. Development of new polysulfides and sealant formulations continues in order to meet market needs of the 1990s. 

If, on the other hand, a vapor cloud s explosive potential is the starting point for, say, advanced design of blast-resistant structures, TNT blast may be a less than satisfactory model. In such cases, the blast wave s shape and positive-phase duration must be considered important parameters, so the use of a more realistic blast model may be required. A fuel-air charge blast model developed through the multienergy concept, as suggested by Van den Berg (1985), results in a more realistic representation of a vapor cloud explosion blast. 

The international temperature scale is based upon the assignment of temperatures to a relatively small number of fixed points , conditions where three phases, or two phases at a specified pressure, are in equilibrium, and thus are required by the Gibbs phase rule to be at constant temperature. Different types of thermometers (for example, He vapor pressure thermometers, platinum resistance thermometers, platinum/rhodium thermocouples, blackbody radiators) and interpolation equations have been developed to reproduce temperatures between the fixed points and to generate temperature scales that are continuous through the intersections at the fixed points. 

The product temperatures were -21.2°C for KC1 and -31.0°C for povidone. The arrows mark the values of the vapor pressure of ice at the operating temperatures. The normalized dried product resistances increase smoothly with pressure as the vapor pressure of ice is approached and exceeded. Thus, the sublimation rate decreases smoothly throughout this pressure range and does not drop to zero at a total system pressure which exceeds the vapor pressure of ice. This observation is completely consistent with the theoretical concepts developed... 

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